United States. Bureau of Labor Statistics.
Proceedings of the Industrial Accident Prevention Conference held at Washington, D.C., July 14-16, 1926 : Bulletin of the United States Bureau of Labor Statistics, No. 428 ,
Washington, D.C.:
Government Printing Office,
September 1926, https://fraser.stlouisfed.org/title/4069,
accessed on November 19, 2018.